1. Field of the Invention
This invention relates to a vehicle interior illumination lamp for mounting on a ceiling of a vehicle.
2. Related Art
There is known the type of vehicle interior illumination lamp for mounting on a vehicle ceiling, in which an integral bus bar, formed by blanking and bending an electrically-conductive metal sheet, is incorporated in a resin-molded housing (see, for example, Unexamined Japanese Patent Publication 2001-180372).
As shown in FIG. 8, this integral bus bar 1 includes contacts 2 forming a switch, an electrical connection portion 3 forming connecting portions for connection to a wire harness, and bulb holding portions 5 for respectively holding terminal portions (opposite end portions) of an incandescent bulb (hereinafter referred to merely as “bulb”) in electrically-connected relation thereto. The contacts 2, the electrical connection portions 4 and the bulb holding portions 5 are wired by wiring bus bars 6.
After the integral bus bar 1 is mounted in the housing, the wiring bus bars 6 are separated from one another at bridge portions 7 interconnecting the wiring bus bars 6, so that the integral bus bar 1 formed into a predetermined circuit construction.
In the integral bus bar 1, the wiring bus bars 6, extending to the contacts 2 and the electrical connection portion 3, are arranged to extend in a longitudinal direction of the integral bus bar 1, that is, in a direction of arrangement of the bulb 4 (which is to be held in the bulb holding portions 5), and are disposed respectively at opposite sides of the bulb holding portions 5, and each pair of holding piece portions 5a, forming the bulb holding portion 5, are disposed between the wiring bus bars 6, and are bent in a direction perpendicular to the longitudinal direction (that is, the direction of arrangement of the bulb 4).
Therefore, in order to provide the holding piece portions 5a, the integral bus bar 1 must be formed in the blanking operation in such a manner that those portions thereof to be formed into the holding piece portions 5a extend in the direction of the width of the integral bus bar 1 as shown in FIG. 9, and therefore the integral bus bar 1 inevitably had an increased size.
Therefore, because of the increased size of the integral bus bar 1, the efficiency of the operation for mounting the interior illumination lamp (employing the integral bus bar 1) in the housing was low, and besides it was difficult to achieve a compact size of the interior illumination lamp